Advice on French Fries and Oil

Q. My 5-year-old daughter has several food allergies (eggs, peanuts, sesame, peas), and recently tested allergic to fish and shellfish. In past, sometimes the only safe thing she could eat at a restaurant was French fries. But now with the fish allergy, I’m wondering: is it OK for the French fries to be fried in the same oil as fish? Some places do serve fish and chips.

Dr. Watson: The question of French fries fried in the same oil as fish is one that I have been asked for many years. In my opinion, it is not safe to eat French fries that are fried in the same oil as fish. Even though the oil is at a very high temperature, I would worry about contamination of the French fries.

I have reviewed the medical literature and cannot find any study to support this opinion, but most allergy information websites recommend avoiding French fries if they have been cooked in the same oil as fish or seafood. Why take a chance?

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Dr. Wade Watson is a pediatric allergist and Professor of Pediatrics at Dalhousie University. He is also the head of the Division of Allergy at the IWK Health Centre in Halifax.